Typically obstructive sleep apnea (OSA) is diagnosed in a sleep laboratory by attaching the patient to various measurement devices, which measure parameters such as an Electroencephalography (EEG), an Electromyography (EMG) of respiratory muscles, a device for measuring blood Oxygen saturation and devices for measuring other parameters while the patient sleeps.
Obstructive sleep apnea is the most common type of sleep apnea. One of its causes is the collapse of the tongue muscle, wherein the collapsed tongue muscle obstructs the airway and causes an OSA event.
Various devices have been designed to enable diagnosing the occurrence of OSA without going to a sleep laboratory. One example is a device that monitors changes in the peripheral arterial tone as manifested by changes in the pulsatile arterial blood volume in a terminal extremity of a body part, e.g. a digit (finger or toe) of the subject, as described in U.S. Pat. No. 7,374,540.
Other methods of diagnosing OSA include implantable systems, for example a system that uses an intra-thoracic pressure sensor that senses breathing movements for treating respiratory disorders as described in U.S. Pat. No. 6,572,543. In US patent application publication no. US 2008/0103407 a system that senses breathing movements by applying an implantable bio-impedance sensor is described. In US patent application publication no. US 2009/0078274 an electro active polymer metal composite sensor is attached to a region in an airway passage of an oral cavity. The electrical output may be wirelessly transmitted to signify an obstructive sleep apnea event.
Other methods include a contact microphone that detects sounds and/or vibrations, and yet other methods include temperature sensors that detect temperature changes when an obstructive sleep apnea event occurs that result from the event.
Upon detection of the occurrence of the OSA event various remedial measures can be taken, for example activating an implanted stimulator or an external device.